Senator Edward J. Markey ducked the first major issue to come before him as a member of the Senate Foreign Relations Committee and the fallout isn’t pretty.

When Markey voted “present” — instead of yes or no — on the question of whether to give President Obama the go-ahead to use military force in Syria, he wasn’t exactly Senator Courageous and that’s putting it kindly.

He’s starting to own the role of acolyte to Senator Elizabeth Warren. And in this case, voting “present” was also a big, surprising slap in the face to Secretary of State John Kerry.

Remember, Markey’s ascension from the House to the Senate is due at least partly to timely backing he got from Kerry, who held the seat for nearly 30 years before moving to Obama’s Cabinet. Kerry’s early endorsement helped Markey solidify support from the rest of the Democratic establishment and kept all challengers but one — US Representative Stephen Lynch — out of the primary. Kerry had Markey’s back. But after Kerry spent more than three hours testifying before the Foreign Relations Committee, Markey did not have Kerry’s back.

In a statement explaining his “present” vote, Markey said he needed more time “to review all relevant classified materials” and was concerned about “unintended consequences.” He also cited language that “could be interpreted as expanding the scope of the US military action beyond merely the degradation and deterrence of Assad’s chemical weapons capability.”

If that sounds familiar, it should. Senator Elizabeth Warren expressed similar sentiments last Monday. After she spoke at Boston’s annual Labor Day breakfast, she told reporters the administration’s proposal was “very open-ended and I think that’s a problem.” She said she wanted to see more data and was concerned about “unintended consequences.”

Warren, who did not have to take a committee vote, has been cautious from the start.

However, Markey initially told the Globe he would support “a surgical set of strikes” if they were made “against sites that could be used to launch chemical weapons.”

“I think it is important for the United States to make this statement and to be a leader on this issue,” he added. Then, after Obama decided to seek congressional support, Markey started walking back his guarded support. “The aftermath of a US strike on targets in Syria is difficult to predict, with negative consequences that go beyond our capability to control,” he said after Obama switched gears.

Markey promises to make up his mind soon. “I will be casting a ‘yea’ or a ‘nay’ on the Senate floor next week,” he told the Globe.

That’s good to know. In the meantime, he’s repeating an early habit of deferring to Warren, as the bigger star and senior senator who beat him to the Senate by half a year. After 37 years in the House, Markey won Kerry’s seat in last June’s special election. He’ll be up for reelection in 2014, and has apparently decided that the best strategy for keeping the seat is sticking close to Warren. Last July, the Globe chronicled a day in life of Markey happily living in Warren’s shadow — or, as the Globe headline put it, basking in her “spotlight.” They are also joining forces on issues. Both voted against a student loan proposal promoted by Obama, despite heavy White House lobbying.

Kerry did a version of this with the late Senator Ted Kennedy. But it’s more notable with Markey, given that he and Warren are both such newcomers to the Senate.

Kennedy and Kerry did not always agree; they split on the 2002 resolution authorizing President Bush to take military action in Iraq. Kennedy opposed the resolution; Kerry voted yes. The question of whether to renounce that vote caused Kerry big headaches during his unsuccessful 2004 run for president.

As a House member, Markey also voted yes on the 2002 Iraq resolution, but “has since made it clear that that vote was based on lies and misinformation given to Congress,” a spokeswoman said. That misjudgment still haunts him, she said, and added to his caution.

Whereever Markey ends up on Syria, it will be harder to blame his vote on “lies and misinformation” since the information comes from fellow Democrats. Markey will have to do what he didn’t do with his committee vote — pick a side and live with the consequences.

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